From 7158627686f02319c50c8d9d78f75d4c8d126ff2 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 5 Nov 2013 18:10:47 +0000 Subject: arm64: percpu: implement optimised pcpu access using tpidr_el1 This patch implements optimised percpu variable accesses using the el1 r/w thread register (tpidr_el1) along the same lines as arch/arm/. Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/setup.c | 10 ++++++++++ arch/arm64/kernel/smp.c | 6 ++++-- 2 files changed, 14 insertions(+), 2 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index bd9bbd0e44ed..97d90840a7fd 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -108,6 +108,16 @@ void __init early_print(const char *str, ...) printk("%s", buf); } +void __init smp_setup_processor_id(void) +{ + /* + * clear __my_cpu_offset on boot CPU to avoid hang caused by + * using percpu variable early, for example, lockdep will + * access percpu variable inside lock_release + */ + set_my_cpu_offset(0); +} + bool arch_match_cpu_phys_id(int cpu, u64 phys_id) { return phys_id == cpu_logical_map(cpu); diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index a0c2ca602cf8..b5d2031c12c6 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -122,8 +122,6 @@ asmlinkage void secondary_start_kernel(void) struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id(); - printk("CPU%u: Booted secondary processor\n", cpu); - /* * All kernel threads share the same mm context; grab a * reference and switch to it. @@ -132,6 +130,9 @@ asmlinkage void secondary_start_kernel(void) current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); + set_my_cpu_offset(per_cpu_offset(smp_processor_id())); + printk("CPU%u: Booted secondary processor\n", cpu); + /* * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries. @@ -271,6 +272,7 @@ void __init smp_cpus_done(unsigned int max_cpus) void __init smp_prepare_boot_cpu(void) { + set_my_cpu_offset(per_cpu_offset(smp_processor_id())); } static void (*smp_cross_call)(const struct cpumask *, unsigned int); -- cgit v1.2.3